β-Carbolines are of great interest due to their broad spectrum of biochemical effects and pharmaceutical functions (Allen, J. R.; Holmstedt, B. R. Phytochemistry 1979, 19, 1573). In particular, there have been intense research efforts in recent years in the design and development of β-carbolines as a new class of antitumor agents. β-Carbolines are initially discovered to exert their antitumor effects by intercalating into DNA. Subsequent investigations suggested that this class of compounds might exert their antitumor effects through multiple mechanisms of action, such as inhibiting topoisomerase I and II (Topo-I and II), cyclin-dependent kinase (CDK), mitogen activated protein kinase-activated protein kinase 2 (MK-2), kinesin-like protein Eg5 and I-Kappa-B kinase (IKK) (Rook, Y.; Schmidtke, K.; Gaube, F.; Schepmann, D.; Weunsch, B.; Heilmann, J.; Lehmann, J.; Winckler, T. J. Med. Chem. 2010, 53, 3611). Further, the importance of β-carboline-based compounds is underscored by the fact that two of these, Tadalafil (Daugan, A.; Grondin, P.; Ruault, C.; de Gouville, A. C. L. M.; Coste, H.; Kirilovsky, J.; Hyafil, F.; Labaudiniere, R. J. Med. Chem. 2003, 46, 4525) and Abecarnil (Turski, L.; Stephens, D. N.; Jensen, L. H.; Peterson, E. N.; Meldrum, B. S.; Patel, S.; Hansen, J. B.; Loscher, W.; Schneider, H. H.; Schmiechen, R. J. Pharmacol. Exp. Ther. 1990, 253, 344) are clinically used for erectile dysfunction and CNS disorders, respectively.

During the last decade, natural products bearing the cinnamoyl moiety have attracted much attention due to their broad spectrum of biological activities and low toxicity. Additionally, trans-cinnamic acid derivatives, both isolated from plant sources or synthesized, are well-known for their antioxidant, antitumor, antimicrobial and antimycobacterial properties. Cinnamic acid derivatives, especially those combining the cinnamoyl moiety with hydroxyl groups' exluitrat free radical scavenging properties. Acids, esters, amides, hydrazides and related derivatives of cinnamic acid with such activities are reported in the literature for their health benefits (Leslie, B. J.; Holaday, C. R.; Nguyen, T.; Hergenrother, P. J. J. Med. Chem. 2010, 53, 3964).